Meaning/Usage: To tell someone to stay out of trouble

Explanation: Normally this is used to tell children to behave appropriately. However, friends use it with one another like they use "stay out of trouble."

"If you're going to have dinner at their house you'd better behave yourself."
"Oh behave yourself, your being naughty."
"Behave yourself when you're at school."

A. "I'm going to go out with the guys this Friday night."
B. "You'd better behave yourself. I know how you guys like to party."
A. "Don't worry, I will be on my best behavior."

Other Common Sentences

"Stay out of trouble."
"Have good manners."